Bipedal Cycling Robot Can Balance, Steer and Correct Itself

Robot creator Masahiko Yamaguchi has demonstrated a robot which can balance, steer and correct itself while riding a fixed-gear bike.

"A feature of this robot is, it pedals the bike with its own feet, and keeps its balance just by using the handlebars. I think this is probably a world first."

"I'm interested in artificial intelligence, and in that context, I think intelligence and skills have equal value. So my purpose in creating this robot was to pursue intelligence from the skills side. While I was thinking of suitable topics, my local science museum demonstrated a cycling robot. So I decided to consider cycling as the skill, and build a bicycle robot."

This robot system consists of a commercially available two-legged robot and a bicycle made by Yamaguchi. To detect how much the robot is tilting, the TAG201 gyro from Tamagawa Seiki is used. Based on the tilt data, a method called PID control is used to control the robot's balancing motion.

"There's a control board in the backpack. That needed to have a high processing speed, so I made my own board using the SH7125 CPU core."

"PID control is a classical control method. It's used to calculate how far to turn the handlebars when the frame tilts. By calculating proportional, integral, and differential components for the tilt, and adding them, the system calculates how far to turn the handlebars when the frame tilts. Also, the robot needs to decide which direction to go in, so we use a remote control to instruct it."

The system has two speeds. Because there aren't any brakes, the robot stops by taking its feet off the pedals and placing them on the ground.

"With an ordinary bicycle, the rear wheel keeps turning even when you stop pedaling. But in a fixed-gear bike, there's no ratcheting, so when you stop pedaling, the rear wheel stops, too. Ordinarily, that makes riding difficult, but with this robot, it also has a braking effect, so a fixed-gear bike is more convenient."

"From now on, I'd like to link this robot's skill to its intelligence. I personally don't like using a remote control for the robot. I'd like to make the robot intelligent enough to ride by itself. This system is the first step toward doing that."